P16.1 Formation of the Solar System Flashcards
What is a comet?
Frozen rocks that move around the Sun in orbits that are elliptical in shape
What is a meteorite?
Small bits of rocks that burn up when they enter the Earth’s atmosphere
What is a protostar?
A concentration of gas and dust that becomes hot enough to cause nuclear fusion
How did the sun start to form?
The particles in the clouds are pulled together by their own gravitational attraction so the particles speed up
Clouds merge together to form a proto star
What happens after the protostar stage?
As the protostar becomes denser - the particles speed up more and collide more - so the temperature increases - The process transfers energy from the protostar’s GPE store to its thermal store
What happens when the protostar gets hot enough?
The nuclei of the hydrogen atoms fuse together to form helium nuclei by nuclear fusion
What is a main sequence star?
When stars radiate energy because of hydrogen fusion in the core - because it is the main stage of their life
Why is the star stable?
Because the forces within it are balanced
What are the forces present around and within the star?
The force of gravity acts inward trying to make the star contract
This is balanced by the outward force of the radiation from nuclear fusion in its core trying to make the star expand
These forces stay in equilibriums until most of the hydrogen has ran out
What is uranium so important?
The presence of uranium on the Earth is evidence that the Solar System must have formed from the remnants of a supernova
